Control questions
- Rules of Conduct in the biological laboratory.
- What hazards can occur in biolaboratoriyi?
- What is a biological hazard?
- Protective equipment used in biological laboratories.
Laboratory work № 1.2.
Methods of studying cells. The structure and procedure of working with light microscopes. The main types of cells. Their structure and main features.
Aim Study of the main features of plant and animal cells.
Objectives Study plants preparates under a light microscope using different lenses. Chemical composition of cells. Characteristics of the main compounds in the cell. Viruses as an intermediate form of life.
Theoretical information
Microscopy-baced methods use a microscope and methods of making microscopic preparations.
There are: optical microscopy, electron microscopy, ion microscopy, atomic force microscopy, X-ray microscopy, laser microscopy.
Microscopic analysis - measuring the size of particles under the microscope and classifying them into groups within the narrow confines of a certain size (for material particle size from 50 microns to tenths of microns).
We know that the possibilities are limited nature of the human eye. Sensitive receptors in the optic nerve in the retina have a relatively small diameter (a few microns), and if the light rays from two points located very close to each other, get to the same receptor, the image of these objects and merges eye does not distinguish between them as two points. Healthy human eye at a distance of 25 cm from the object forms an image of two points last separately if they are at a distance of not less than 0.1 mm. The shortest distance between two points, an image which forms the eye alone, called resolutional distance. The lower it to a specific device, the greater its resolution (d). In order to increase the resolution of the eye, people have long started to use magnifying glasses (lenses). These were relatively simple microscopes. Modern microscopes are arranged essentially the same and actually are the same improved microscope. They consist of mechanical and optical parts (Fig. 1.2.).
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fig. 1. Scheme of microscope MBP – 1
1 - stand, 2 - box with micromechanism 3 - macrometric screw 4 - micrometric screw, 5 - tubeholder 6 - mono or binocular attachment, 7 - eyepiece 8 - revolver Lens, 9 - lenses, 10 - the stage, 11 - condenser, 12 - condenser bracket 13 - condenser handle, 14 – mirror (or light source).
Equipment, materials and methods.
Microscope objective lenses, glasses with hole, glass rods, hinges, cover lenses.
Plants higher.
The order of performance and recommendations
- Obtain samples of living cells and tissues.
- Prepare for microscopy native (unpainted preparatess) types "hanging drop" and "crushed drop."
- Prepare smears and other preparations for painting.
- Fix samples chemically and thermally
- Conduct coloring technique.
- These preparates mikroskopuvaty. To fix the image on all available degrees of increase, from less to most.
- Compare appearance of cells fixed and painted and native.
- Set clear image of moving the condenser.
Control questions
- what Biological Laboratory Equipment do you know?
- The concept of sterility, antiseptics, asepsics;
- Laboratory equipment that promotes safety work in biological laboratories.
- Define microscopy as a method.
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